Nuclear energy has been used as a power source for approximately the last 50 years. The nuclear reactors providing that power have been producing waste since that time. That waste has created significant problems.
There are approximately 110 active nuclear reactors in the United States, each producing an average of 20 metric tons of nuclear waste. A nuclear power facility ordinarily stores this waste in an on-site indoor water pool. However, these facilities are quickly reaching their storage capacity.
By 1998, 32 nuclear reactors will have no more indoor water pool storage capacity. To address this problem, the federal government in 1982 enacted the Nuclear Waste Policy Act which mandated that the federal government accept nuclear waste beginning Jan. 31, 1998. As of today, the federal government does not have a concise definitive plan in place to deal with the nuclear waste it will receive. Indeed, the proposed federal repository site at Yucca Mountain is years behind schedule. Further, because of earthquakes and transportation problems there is no guarantee that the Yucca Mountain facility will ever be completed.
Adding to the problem of excess nuclear waste is the fact that many nuclear power plants are likely to close in the next two decades. When these reactors are closed, the waste at those power plants must also be handled.
The disposal of nuclear waste raises serious questions regarding public safety. The recognized harm (for example, cancer) caused by high levels of radiation exposure have caused a great deal of public concern about radiation from nuclear power plants and about radiation generally. This public concern and other concerns have made it difficult for public utilities to create permanent nuclear waste facilities. For example, permanent facilities may involve storing the nuclear waste below ground level which raises issues related to underground water contamination. Underground facilities are also difficult to monitor and maintain and make retrieving the waste for reprocessing difficult.
To address these problems, many utilities are pressing the federal government to license rugged above-ground containers for either temporary or permanent storage. Rugged above-ground containers are called dry casks, and to date, are only temporary in nature. Dry casks are ordinarily constructed from concrete and steel and are placed on a concrete base. The nuclear waste is then placed in the cask. An example of one such cask is disclosed in U.S. Pat. No. 4,527,066 to Dyek entitled "CONCRETE SHIELDING HOUSING FOR RECEIVING AND STORING A NUCLEAR FUEL ELEMENT CONTAINER." Other casks are available in the prior art as well.
Above-ground storage in casks raise significant public concerns as well. The public concerns are exacerbated by the fact that facilities which were designed to be temporary are quickly becoming considered to be permanent. The concerns include the possible discontinuance of maintenance, sabotage, and difficulties in transportation.
Maintenance of these above-ground casks is critical because of their concrete construction. With proper maintenance, scientists have speculated that concrete used in nuclear applications may have a service life of up to 60 years. See Hookham & Bailey, Long Term Durability Considerations for Nuclear Power Plant Structures 1990. However, if a facility is permanent, 60 years is a very short time as compared to the long-term toxicity of nuclear waste. Problems associated with concrete structures include cracking and deterioration. These problems are caused in part by freeze/thaw cycling of water in addition to the additional corrosive affects caused by acid rain. As concluded by Hookham and Bailey, without proper maintenance these environmental factors will eventually render a concrete structure unsafe.
When these problems occur, the concrete must be repaired and/or replaced. To properly perform maintenance, the dry cask must be continually monitored so that cracks and erosion can be repaired immediately. The process of continually monitoring and repairing is extremely costly. As budgets are cut back, additional concerns arise because these concrete structures may fall out of repair thereby shorting their useful life. If maintenance is discontinued, the structure would erode thereby compromising its integrity.
Because the potential harm which would be caused by a nuclear radiation leak is so great, facilities must protect against sabotage or attack. Sabotage may take the form of launched projectiles, or direct attack by suicide or truck bombers. Thus, storage facilities must provide a high degree of security.
Safe transportation of nuclear waste is also an issue which must be addressed. The primary issue related to transportation is the public's unwillingness to allow high sources of radiation traveling past homes and exposing people to the radiation. To avoid these problems, nuclear power plants prefer to store waste on site.
Therefore, a need has arisen to prevent the potential harm to the public should maintenance of these temporary facilities cease, or should the temporary casks be compromised. A further need has arisen to make the temporary sites which are becoming permanent safer.